mtip32xx: Add new sysfs entry 'status'

* Add support for detecting the following device status
        - write protect
        - over temp (thermal shutdown)
* Add new sysfs entry 'status', possible values - online, write_protect, thermal_shutdown
* Add new file 'sysfs-block-rssd' to document ABI (Reported-by: Greg Kroah-Hartman)
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/ABI/testing/sysfs-block-rssd

+What:           /sys/block/rssd*/registers
+Date:           March 2012
+KernelVersion:  3.3
+Contact:        Asai Thambi S P <asamymuthupa@micron.com>
+Description:    This is a read-only file. Dumps below driver information and
+                hardware registers.
+                    - S ACTive
+                    - Command Issue
+                    - Allocated
+                    - Completed
+                    - PORT IRQ STAT
+                    - HOST IRQ STAT
+
+What:           /sys/block/rssd*/status
+Date:           April 2012
+KernelVersion:  3.4
+Contact:        Asai Thambi S P <asamymuthupa@micron.com>
+Description:   This is a read-only file. Indicates the status of the device.

drivers/block/mtip32xx/mtip32xx.h

@@ -127,6 +127,19 @@
 #define MTIP_DD_FLAG_CLEANUP_BIT		3
 #define MTIP_DD_FLAG_INIT_DONE_BIT		4
 
+#define MTIP_DD_FLAG_WRITE_PROTECT_BIT		5
+#define MTIP_DD_FLAG_OVER_TEMP_BIT		6
+#define MTIP_DD_FLAG_REBUILD_FAILED_BIT		7
+
+__packed struct smart_attr{
+	u8 attr_id;
+	u16 flags;
+	u8 cur;
+	u8 worst;
+	u32 data;
+	u8 res[3];
+};
+
 /* Register Frame Information Structure (FIS), host to device. */
 struct host_to_dev_fis {
 	/*
@@ -351,6 +364,12 @@ struct mtip_port {
 	 * when the command slot and all associated data structures
 	 * are no longer needed.
 	 */
+	u16 *log_buf;
+	dma_addr_t log_buf_dma;
+
+	u8 *smart_buf;
+	dma_addr_t smart_buf_dma;
+
 	unsigned long allocated[SLOTBITS_IN_LONGS];
 	/*
 	 * used to queue commands when an internal command is in progress